diff --git a/compiler/kernel/vexpr.go b/compiler/kernel/vexpr.go
index 7b39a55681..833caf9ef4 100644
--- a/compiler/kernel/vexpr.go
+++ b/compiler/kernel/vexpr.go
@@ -133,9 +133,8 @@ func (b *Builder) compileVamUnary(unary dag.UnaryExpr) (vamexpr.Evaluator, error
 		return nil, err
 	}
 	switch unary.Op {
-	//XXX TBD
-	//case "-":
-	//	return vamexpr.NewUnaryMinus(b.zctx(), e), nil
+	case "-":
+		return vamexpr.NewUnaryMinus(b.zctx(), e), nil
 	case "!":
 		return vamexpr.NewLogicalNot(b.zctx(), e), nil
 	default:
diff --git a/runtime/sam/expr/eval.go b/runtime/sam/expr/eval.go
index 71e3f27559..244332f687 100644
--- a/runtime/sam/expr/eval.go
+++ b/runtime/sam/expr/eval.go
@@ -545,6 +545,26 @@ func NewUnaryMinus(zctx *super.Context, e Evaluator) *UnaryMinus {
 func (u *UnaryMinus) Eval(ectx Context, this super.Value) super.Value {
 	val := u.expr.Eval(ectx, this)
 	typ := val.Type()
+	if super.IsUnsigned(typ.ID()) {
+		switch typ.ID() {
+		case super.IDUint8:
+			typ = super.TypeInt8
+		case super.IDUint16:
+			typ = super.TypeInt16
+		case super.IDUint32:
+			typ = super.TypeInt32
+		default:
+			typ = super.TypeInt64
+		}
+		v, ok := coerce.ToInt(val, typ)
+		if !ok {
+			return u.zctx.WrapError("cannot cast to "+zson.FormatType(typ), val)
+		}
+		if val.IsNull() {
+			return super.NewValue(typ, nil)
+		}
+		val = super.NewInt(typ, v)
+	}
 	if val.IsNull() && super.IsNumber(typ.ID()) {
 		return val
 	}
@@ -575,30 +595,6 @@ func (u *UnaryMinus) Eval(ectx Context, this super.Value) super.Value {
 			return u.zctx.WrapError("unary '-' underflow", val)
 		}
 		return super.NewInt64(-v)
-	case super.IDUint8:
-		v := val.Uint()
-		if v > math.MaxInt8 {
-			return u.zctx.WrapError("unary '-' overflow", val)
-		}
-		return super.NewInt8(int8(-v))
-	case super.IDUint16:
-		v := val.Uint()
-		if v > math.MaxInt16 {
-			return u.zctx.WrapError("unary '-' overflow", val)
-		}
-		return super.NewInt16(int16(-v))
-	case super.IDUint32:
-		v := val.Uint()
-		if v > math.MaxInt32 {
-			return u.zctx.WrapError("unary '-' overflow", val)
-		}
-		return super.NewInt32(int32(-v))
-	case super.IDUint64:
-		v := val.Uint()
-		if v > math.MaxInt64 {
-			return u.zctx.WrapError("unary '-' overflow", val)
-		}
-		return super.NewInt64(int64(-v))
 	}
 	return u.zctx.WrapError("type incompatible with unary '-' operator", val)
 }
diff --git a/runtime/vam/expr/unaryminus.go b/runtime/vam/expr/unaryminus.go
new file mode 100644
index 0000000000..79071d32a3
--- /dev/null
+++ b/runtime/vam/expr/unaryminus.go
@@ -0,0 +1,150 @@
+package expr
+
+import (
+	"math"
+
+	"github.com/brimdata/super"
+	"github.com/brimdata/super/runtime/vam/expr/cast"
+	"github.com/brimdata/super/vector"
+)
+
+type unaryMinus struct {
+	zctx *super.Context
+	expr Evaluator
+}
+
+func NewUnaryMinus(zctx *super.Context, eval Evaluator) Evaluator {
+	return &unaryMinus{zctx, eval}
+}
+
+func (u *unaryMinus) Eval(this vector.Any) vector.Any {
+	return vector.Apply(true, u.eval, u.expr.Eval(this))
+}
+
+func (u *unaryMinus) eval(vecs ...vector.Any) vector.Any {
+	vec := vector.Under(vecs[0])
+	if vec.Len() == 0 {
+		return vec
+	}
+	if _, ok := vec.(*vector.Error); ok {
+		return vec
+	}
+	id := vec.Type().ID()
+	if !super.IsNumber(vec.Type().ID()) {
+		return vector.NewWrappedError(u.zctx, "type incompatible with unary '-' operator", vecs[0])
+	}
+	if super.IsUnsigned(id) {
+		var typ super.Type
+		switch id {
+		case super.IDUint8:
+			typ = super.TypeInt8
+		case super.IDUint16:
+			typ = super.TypeInt16
+		case super.IDUint32:
+			typ = super.TypeInt32
+		default:
+			typ = super.TypeInt64
+		}
+		return u.eval(cast.To(u.zctx, vec, typ))
+	}
+	out, ok := u.convert(vec)
+	if !ok {
+		// Overflow for int detected, go slow path.
+		return u.slowPath(vec)
+	}
+	return out
+}
+
+func (u *unaryMinus) convert(vec vector.Any) (vector.Any, bool) {
+	switch vec := vec.(type) {
+	case *vector.Const:
+		var val super.Value
+		if super.IsFloat(vec.Type().ID()) {
+			val = super.NewFloat(vec.Type(), -vec.Value().Float())
+		} else {
+			v := vec.Value().Int()
+			if v == minInt(vec.Type()) {
+				return nil, false
+			}
+			val = super.NewInt(vec.Type(), -vec.Value().Int())
+		}
+		return vector.NewConst(val, vec.Len(), vec.Nulls), true
+	case *vector.Dict:
+		out, ok := u.convert(vec.Any)
+		if !ok {
+			return nil, false
+		}
+		return &vector.Dict{
+			Any:    out,
+			Index:  vec.Index,
+			Counts: vec.Counts,
+			Nulls:  vec.Nulls,
+		}, true
+	case *vector.View:
+		out, ok := u.convert(vec.Any)
+		if !ok {
+			return nil, false
+		}
+		return &vector.View{Any: out, Index: vec.Index}, true
+	case *vector.Int:
+		min := minInt(vec.Type())
+		out := make([]int64, vec.Len())
+		for i := range vec.Len() {
+			if vec.Values[i] == min {
+				return nil, false
+			}
+			out[i] = -vec.Values[i]
+		}
+		return vector.NewInt(vec.Typ, out, vec.Nulls), true
+	case *vector.Float:
+		out := make([]float64, vec.Len())
+		for i := range vec.Len() {
+			out[i] = -vec.Values[i]
+		}
+		return vector.NewFloat(vec.Typ, out, vec.Nulls), true
+	default:
+		panic(vec)
+	}
+}
+
+func (u *unaryMinus) slowPath(vec vector.Any) vector.Any {
+	var nulls *vector.Bool
+	var ints []int64
+	var errs []uint32
+	minval := minInt(vec.Type())
+	for i := range vec.Len() {
+		v, isnull := vector.IntValue(vec, i)
+		if isnull {
+			if nulls == nil {
+				nulls = vector.NewBoolEmpty(vec.Len(), nil)
+			}
+			nulls.Set(uint32(len(ints)))
+			ints = append(ints, 0)
+			continue
+		}
+		if v == minval {
+			errs = append(errs, i)
+		} else {
+			ints = append(ints, -v)
+		}
+	}
+	if nulls != nil {
+		nulls.SetLen(uint32(len(ints)))
+	}
+	out := vector.NewInt(vec.Type(), ints, nulls)
+	err := vector.NewWrappedError(u.zctx, "unary '-' underflow", vector.NewView(vec, errs))
+	return vector.Combine(out, errs, err)
+}
+
+func minInt(typ super.Type) int64 {
+	switch typ.ID() {
+	case super.IDInt8:
+		return math.MinInt8
+	case super.IDInt16:
+		return math.MinInt16
+	case super.IDInt32:
+		return math.MinInt32
+	default:
+		return math.MinInt64
+	}
+}
diff --git a/runtime/sam/expr/ztests/unary-minus.yaml b/runtime/ztests/expr/unary-minus.yaml
similarity index 95%
rename from runtime/sam/expr/ztests/unary-minus.yaml
rename to runtime/ztests/expr/unary-minus.yaml
index d8fee7e48e..9245786350 100644
--- a/runtime/sam/expr/ztests/unary-minus.yaml
+++ b/runtime/ztests/expr/unary-minus.yaml
@@ -1,5 +1,7 @@
 zed: yield -this
 
+vector: true
+
 input: |
   1(int8)
   -1(int8)
@@ -66,10 +68,10 @@ output: |
   null(int16)
   null(int32)
   null(int64)
-  null(uint8)
-  null(uint16)
-  null(uint32)
-  null(uint64)
+  null(int8)
+  null(int16)
+  null(int32)
+  null(int64)
   null(float16)
   null(float32)
   null(float64)
diff --git a/vector/bool.go b/vector/bool.go
index b0a23d9edb..289d24720c 100644
--- a/vector/bool.go
+++ b/vector/bool.go
@@ -39,6 +39,10 @@ func (b *Bool) Set(slot uint32) {
 	b.Bits[slot>>6] |= (1 << (slot & 0x3f))
 }
 
+func (b *Bool) SetLen(len uint32) {
+	b.len = len
+}
+
 func (b *Bool) Len() uint32 {
 	if b == nil {
 		return 0